Folding protractor-square.



J. BARKER.

FOLDING PROTRACTOR SQUARE. APPLICATloN FILED Nov. 23. 19m.

1,161,761. y Patented Nov. 23, 1915.

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J. BARKER.

FOLDING PROTRACTOR SQUARE.

APPLIcATloN FILED Nov.23.1914.

2 SHEETS-SHEET 2.

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UNITED STATES PATENT OFFICE.

JOI-IN BARKER, OF `LOS ANGELES, CALIFORNIA, ASSIGNOR TO ALL ANG-LE SQUARE COMPANY, 0F LOS ANGELES, CALIFORNIA, A CORPORATION 0F CALIFORNIA.

' FOLDING PROTRACTOR-SQUARE.

riemei.

To all .t0/wm t may concern Beit known that I, JOHN BAKKER, a citi- Zen of theUnited States, residing at Los Angeles, in the county of Los Angeles, State of California, have invented new and useful Improvements in Foldingl Protractor- Squares, of which the following is a specilication.

This invention relates to improvements in carpenters folding protractor squaresof the character shown in my Patents Nos. 952,176; 952,177; and 1,043,502; and the invention has particularly to do with certain improvements and novelties of construction and operation which are hereinafter pointed out. Among these improvements, I may mention the construction by which the arm and blade of the square fold together, and the construction which enables direct readings to be taken from the square for certain purposes, where heretofore it has been impossible to take such direct'readings.

In the following specification I describe a preferred form of my square and show the same in the accompanying drawings in which- Figure 1 is a plan of my improved square 'in its extended position, Fig. 2 shows the square in its folded position, Fig. 3 is a reduced view showing the square in use, Fig. 4 is an end view of the square as shown in Fig. 2. Fig. 5 is a section taken as indicated by line 5 5 of Fig. 2. Fig.v 6 is a'section similar to Fig. 5 showing a modified form of construction, Fig. 7 is a section taken as indicated by line 7-7 of Fig.-2, Fig. 8 is a section showing the pivot construction between the arm and blade, and Fig. 9 is a section taken as indicated by line 9 9 of Fig. l.

In the drawings the numeral 10 designates the arm of my square while the numeral 11 designates the blade thereof, the blade 11 being movable upon arm 10 at the pivot 12. This pivot l2 is formed as is best shown in detail in Fig. 8, with a screw 13 for tighten.- ing the pivotal connection to keep it in accurate adjustment. The arm 10 is provided with a semi-circular recess 14 into which a corresponding circular tongue 15 of the blade 11 is adapted to lit. The recess 14 has an under-cut channel 16 and the tongue 15 has a rib 17 adapted to fit in this under-cut channel 16. The longitudinal edge'of the arm l0 has a longitudinal groove 20 in which a corresponding tongue .21 on the Specification of Letters Patent.

'tongue 21a.

Patented Nov. 23, 1915.

Application filed November 23, 1914. Serial No. 873,454.

blade 11 is adapted to fit, when the arm and blade are folded together as shown inFig. 2. This interlocking of the arm and blade and tongue tends to make the square solid when it is either extended or folded, preventing either the arm or blade being accidentally bent or broken and making the whole construction solid and accurate. In Fig. 6 I have shown the arm 10-having a rabbet 20il and the blade 11 having a corresponding I employ suitable means to lock the arm and blade in position at right angles to each other and also in-.any position at an acute .K angle to reach other. A movable locking bolt 30 1s mounted in a suitable way 31`cut in the arm 10 and is` adapted to engage with a notch 32V in the tongue 15 of blade 11,

holding the blade in its right angled position. To hold the blade in any intermediate acute angled` positi'on,-I` provide a locking dog 35 adapted to be drawn down byscrew 36 tightly onto the rib 17, thus to hold the blade in any desiredposition. The circular edges of the recess 14- and the tongue 15 may be providedwith circular divisions aci cording to any desired system. Thus, I may provide the arm 10 with degree divisions 40 along the edge of recess 14; and an arrow or other mark 411 on the tongue 15 may indicate the proper reading on this degree scale. And I may place scale marks i2 on the edge of tongue 15; and these scale marks may indicate positions of theblade corresponding to different roof pitches; that is, theV ratio of rise tol horizontal traverse or span. These scale indications may be placed on the tongue l5 so as to be readable against any suitable mark on the arm, say against the zero mark of the degree scale. These divisions, or any other suitable ones, may be employed, I may employ the scale of pitches exclusively, or the degree scale eX- clusively, or both as illustrated. There is some rconsiderable advantage in utilizing both the pitch and degree scales. In some cases it is very desirable to set the square directly to pitch without the necessity of translating the pitch terms to terms of degrees. In other cases, as when angularcuts are being laid off for polygons, etc., it is necessary to have a vscale reading directly in degrees. A Y' V The locking bolt 30 is pressed V'forward by a small spring 4:5 which is set in the recess 31 beneath the bolt 30. i 'A thin extension 30a of the bolt 30 serves to cover the recess 31, and to prevent accumulation of dirt therein. lThe shallow recess 31a necessary to accommodate the shallow cover 30a does not afford lodgment for dirt or the like. The upper surface of the bolt is knurled so as to be engageable by the thumb or finger.

@n the inner opposing edges of thearm l0 and blade 11 I provide linear scale divisions 46 and 47, each of which divisions has its zero or beginning point at the pivot 12, or a line passing transversely through the port 12. These linear scales 46 and 47 are preferably divided into inches and twelfths, so that each scale becomes in effect a scale representing one foot to the inch and one inch to each twelfth of an inch. In practical use, this provision is of great importance. Supposing that it is desired to cut a set of rafters for a building 11 feet wide with a roof of one'fourth pitch. The blade is set to one-fourth pitch (or, if the pitch divisions are not directly upon the square, the blade may be set to the angular position corresponding to one-fourth pitch) and the angle of out for both ends of the rafter is thus immediately given. To ascertain the exact length ofthe rafter, it is only necessary toL proceed as indicated inFig. 3. A try-square is placed on the' arm 10 at the 5th and one half division (indicating a half-width of the building) and the reading of the scale 4T is taken where the blade 50a of the try-square intersects the `edge of the blade 11. This givesdirectly the rafter length. The heightof the rafter ridge can be read off the try-square bla-de 50a. For different lengths of rafter at the same pitch, it is only necessary to slide the try-square to different positions. It .will be noted that the edge of the arm is graduated so that it can be numbered both from the pivot center and from the corner c The numbers reading from the pivot center are the ones which are read in obtaining the length of a rafter; and in the ordinary use of the square the other numbers are yused reading from the corner C Thus, although `the ordinary use of the square is not interfered with, the rafter lengths are read directly off the scale without any computation, etc. The cuts for the rafter ends are also directly obtainable; one at the angle between the blade 10 and arm 11 and the other at the angle between arm 11 and blade 50a of the try-square.

Besides the linear scales herein described, and the ordinary linear scales on the outer edges of the square, the arm blade of my square may have thereon'various info-rmation tables. For instance, I' may illustrate various polygons, as shown at 51 giving the angle by which Vthe sides of any one may be ylaid out, that is, the angle between one side and a prolongation of an adjacent one.

I may also havetables showin0` the angles C 2D in degrees corresponding to diiferent roof pitches; and I may also have tables showing the lengths of rafters for different pitches per foot of horizontal distance. These various tables may be used in connection with the protractor features of my square and make my square a tool of universal use. In fact, my square takes the place of a number of tools Aand is generally useful in a great variety of circumstances where an ordinary square could not be used.

In conclusion, I wish to draw particular attention to the features herein set forth, including the arrangement for easily and directly obtaining the cuts and lengths of raftersand all other angular or diagonal members and the mechanical construction and connection and interlocking of the parts of the square. f

Having described my invent-ion, I claim:

1. In a folding protractor square, the combination of an arm and a. blade pivoted together at a point on a line with the inner edge of the blade and within the body of the arm, the arm and blade having complementary tongue and groove formations on their inner edges of a depth equal to the distance of the pivot from the inner edge of the arm. the arm and blade having circular scales to indicate their relative positions in terms of angular measure and of pitch, and the arm and blade having linear scales on the inner edges, said scales having their zero points opposite the pivotal point, substantially as described. f

2. In a folding protractor square, the combination of an arm and a blade pivoted together at a point on a line with the inner edge ofthe blade and within the body of the arm, the arm and blade having complementary tongue and groove formations on their inner edges of a depth equal to the distance of the pivotal point from the innerk edge of the arm, the arm and the blade having circular scales to indicate their relative positions in terms of angular measure and of pitch, means to hold the arm and blade in any desiredy angular position, means to lock the arm and blade at right angles to each other, and the arm and blade having linear scales on their inner edges, said scales havingtheir zero points opposite the pivotal point, substantially as described.

In witness that I claim the foregoing I have hereunto subscribed my name this 16 day of November, 1914. y

Y JOHN BARKER.

Witnesses: JAMES T. BARKELEW, A

` ELwooD H. BARKELEW Copies of this patent may be obtained for five cents each, by addressing the Commissioner"ofv Patents,

Washington, D. C. 

